LOS ANGELES (AP) — A preliminary study Tuesday estimated that the Republican plan to replace the national health care overhaul would deliver a financial jolt to elderly, lower-income Californians, potentially leaving tens of thousands without coverage.

The analysis by state insurance exchange Covered California comes a day after the Congressional Budget Office estimated that 14 million people would lose insurance coverage in the first year under the GOP proposal.

Overall, millions of Californians would be in danger of being pushed out of the insurance market under the plan, Peter Lee, the executive director of Covered California, told reporters. Under the Obama administration, about 5 million Californians gained coverage through the Affordable Care Act and an expansion in Medicaid, which covers the needy, he said.

About 90 percent of the 1.5 million new and renewing enrollees at Covered California receive subsidies.

Potential deep cuts in tax credits under the Republican-backed American Health Care Act would mean “there are going to be fewer people covered,” Lee said.

The White House has disputed CBO’s projections about how many Americans would lose coverage, while highlighting the agency’s conclusions that the GOP bill would reduce the deficit by $337 billion over a decade. The GOP legislation would use tax credits to help consumers buy health coverage, expand health savings accounts, phase out an expansion of Medicaid and cap that program for the future, end some requirements for health plans under Obama’s law, and scrap a number of taxes.

Under current law, financial assistance is based on age, income, family size and where the consumer lives. Under the GOP plan, age would become the primary factor.

In California, its impact for those enrolled in subsidized coverage would vary widely.

The report says a 62-year-old in Los Angeles earning $30,000 a year in a lower-tier plan would see an estimated net premium increase of about $70, to $275 per month, under the proposed law.

But if that person lived in San Francisco, the premium would jump an estimated $460, to $668 per month, under the change.

“For older Californians, the effect of the proposed tax credit structure is a dramatic increase in the out-of-pocket costs for coverage, meaning they are likely to drop coverage,” the report concluded.

Covered California was created in 2010, when the state became the first to embrace the Affordable Care Act.

As a candidate, President Donald Trump promised to repeal and replace the act. House Speaker Paul Ryan has predicted the bill will pass the House next week.

Lee warned the changes could unsettle the nation’s broader insurance market, beyond Medicaid and those who purchase coverage through public exchanges.

“Health care is a woven fabric that is connected,” he said.

The Republican plan to replace Obamacare also comes with a big catch-22 for California in regards to family planning.

Amy Everitt, the California State Director of the National Abortion Rights League, explained the problem.

“You cannot use any tax credits to buy a plan that covers abortion care,” said Everitt. “And the challenge for California is that we mandated — because we actually respect women and their dignity and making personal health decisions — every health plan in California has to cover abortion care. So they are in direct conflict of one another.”

California law says all insurance plans have to provide “basic health services.” That includes “family planning services.”

“I believe it was in 1981 that California Supreme Court ruled that you have to consider abortion and a maternity care and birth control access neutral,” said Everitt. “So if you’re going to provide maternity care you also have to provide abortion care of family planning services.”

But the Republican proposal is clear. “No funds authorized or appropriated” by the act can pay for “any health plan the covers abortion.” That means Californians who get tax credits can’t use them to buy insurance in the state.

“We are facing a bit of a collision course,” said Jonathan Keller, the President and CEO of the California Family Council.

He says it’s up to California to change its law.

“I think the danger here is that, if California does not change course, then they would be putting their citizens at risk for not being eligible for these federal subsidies,” said Keller.

A group of churches has already sued the state of California over the abortion coverage requirement. That case is set to go to trial in June of next year.